While there are dozens of hangover cures, the most effective are those that are taken before the drinking occurs. Hangover pain is mostly from dehydration, allergic impurities in the alcohol and poisoning known as acetaldehyde damage.
Speaking from experience, drinking plenty of water before and during drinking, can lessen the effects of the alcohol. Drinking alcohol with fewer impurities in it can also lessen hangovers. For example, good quality vodka will tend to give the drinker less of a hangover than dark rum. You can also visit at http://sober-on.com/ to get more data related to hangover cures.
My best drinking experience, as a young soldier, was fruit juice with medical alcohol. I only suffered some fatigue and dehydration without the usual blood shot eyes, headaches and nausea.
However, be very, very careful when drinking any kind of "medical alcohol." The DIETHYL alcohol is relatively safe in moderate quantities.
But METHYL alcohol (aka wood or rubbing alcohol) is poisonous and can kill you. Several soldiers once drank a punch made from methyl alcohol. One went blind and another died. This is another good reason to stick with bottled drinks when visiting strange establishments.
Aside from drinking plenty of water between drinks, you should also eat before and during drinking. Fruits will supply water and electrolytes, but proteins and fats will slow down the absorption of alcohol.
Unfortunately, most pubs try to encourage thirst by feeding their patrons pretzels, chips and crackers. Mostly empty carbohydrates. If you can, snack on meats, seafood and cheese.